Study: Even the Slightest Decrease in Deep Sleep Can Elevate Risk of Alzheimer's Disease

Key TakeawaysA recent study found that the slightest decrease in deep sleep can elevate a person’s risk of Alzheimer’s disease.Deep sleep naturally declines as people age, but this decline is greatest among people in their 70s.Researchers theorize that the lack of deep sleep can prevent the body from removing amyloid, which is thought to be involved in Alzheimer’s disease.

Key Takeaways

A recent study found that the slightest decrease in deep sleep can elevate a person’s risk of Alzheimer’s disease.Deep sleep naturally declines as people age, but this decline is greatest among people in their 70s.Researchers theorize that the lack of deep sleep can prevent the body from removing amyloid, which is thought to be involved in Alzheimer’s disease.

During a typical night, a person goes throughfour stages of sleep: stage 1 (initially falling asleep), stage 2 (light sleep), stage 3 (deep sleep, or slow-wave sleep), and rapid eye movement (REM) sleep, when the brain is particularly active. The significance of these sleep stages extends far beyond restfulness.

Research has consistently linked insufficient or poor sleep quality to a weakened immune system, poorer mental health outcomes, and increased risk of disease. These findings underscore theimportance of maintaining proper sleep hygiene.

A new research study reveals another connection between sleep and cognitive health: Even a small decrease in stage 3 deep sleep can elevate your Alzheimer’s risk.

What Counts as Deep Sleep?

Deep sleep, also known as slow-wave sleep, is the deepest stage of sleep.

Researchers looked at 346 participants over 60 years of age enrolled in the Framingham Heart Study who completed two overnight sleep studies (1995 to 1998 and 2001 to 2003). These patients were monitored carefully for signs of dementia in the years following their participation.

On average, the researchers found that the amount of deep sleep declined from the second sleep study to 2018. Researchers followed up with the patients over the next 17 years, identifying 52 cases of dementia. Each percentage decrease in deep sleep was associated with a 27% increase in dementia risk.

Baril theorizes the sleep/Alzheimer’s connection may exist because a lack of deep sleep prevents the brain from adequately clearing proteins likeamyloid. A buildup of amyloid plaques is linked to neuron damage and atrophy in the brain—though it’s not the only possible cause of Alzheimer’s.

Factors that Influence Deep Sleep

According toMatthew Pase, PhD, lead author of the study and associate professor at the Turner Institute at Monash University in Australia, declines in slow-wave sleep over time were greatest among people in their 70s.

Baril emphasized there’s no set rate of decline: How much sleep quality declines varies from person to person.

“Slow-wave sleep tends to decline as we get older, which is also observed in the current study since slow-wave sleep declined over time with age,” Baril said. “This decline is thought to occur progressively through adulthood.”

Other than age, sleep disorders and poor sleep habits can have a direct impact on the amount of deep sleep people get. Baril said that the optimal amount of deep sleep remains unclear. During a typical sleep cycle, people get a few minutes of deep sleep every 90 minutes, resulting in about 20% of the total duration of the night.

To get more deep sleep, Baril recommends sticking to good, simple sleep habits, such as reducing your caffeine intake later in the day, maintaining a regular sleep schedule, and exercising often.

What This Means For YouWhile there’s no proven way to prevent Alzheimer’s, a new study suggests getting more deep sleep can’t hurt. The best and easiest ways to improve deep sleep are to keep your bedtime routine regular and to exercise.

What This Means For You

While there’s no proven way to prevent Alzheimer’s, a new study suggests getting more deep sleep can’t hurt. The best and easiest ways to improve deep sleep are to keep your bedtime routine regular and to exercise.

1 SourceVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Himali JJ, Baril AA, Cavuoto MG, et al.Association between slow-wave sleep loss and incident dementia.JAMA Neurol. Published online October 30, 2023. doi:10.1001/jamaneurol.2023.3889

1 Source

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Himali JJ, Baril AA, Cavuoto MG, et al.Association between slow-wave sleep loss and incident dementia.JAMA Neurol. Published online October 30, 2023. doi:10.1001/jamaneurol.2023.3889

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

Himali JJ, Baril AA, Cavuoto MG, et al.Association between slow-wave sleep loss and incident dementia.JAMA Neurol. Published online October 30, 2023. doi:10.1001/jamaneurol.2023.3889

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